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[en] The phase diagram for a gallium-indium alloy shows that the eutectic is formed at a temperature of 15.3 C and has a eutectic composition of 14.2 at. pct In (21.4 wt pct In). A eutectic melt is expected to solidify completely when the eutectic temperature is reached. This requires that no gravitational segregation occurs in the melt. A survey of the available literature on eutectic Ga-In revealed no prior experiments on the in situ visualization of solidification. The goal of this experimental work was to observe the isothermal solidification of a vertical layer of molten eutectic Ga-In in real-time using X-ray radioscopy

[en] While studying the growth of gallium crystals in the alloys Ga + 10% In and Ga + 6% Sn by a direct observation under a microscope in a reflected polarized light the kinetics of separation of primary gallium crystals has been investigated. It is shown that the threshold supercooling below which no displacement of crystal faces is observed differs neglibly both for pure gallium and for its alloys, the threshold supercooling value is depending on a substrate. The obtained time dependences of the crystal size under supercooling close to a threshold one show that the growth rate increases with increasing the area of the face. The loss in a stable growth of a flat-face crystal gallium is studied; it is found that the loss in stability results from liquid impurities, or from the formation of defects in central areas of faces

[en] Differential scanning calorimetry (DSC) technique was used to study the kinetics of amorphous to crystalline transformation for Ga_xSe_100-x glass system (x=0, 2.5 and 5 at%). The kinetic parameters of Ga_xSe_100-x glass system under non-isothermal conditions are analyzed by the model-free and model-fitting models at different constant heating rates (5-50 K/min). A strong heating rate dependence of the effective activation energy of crystallization was observed. The analysis of the present data shows that the effective activation energy of crystallization is not constant but varies with the degree of crystallization and with temperature as well. The crystallization mechanisms examined using the local Avrami exponents indicate that one mechanism (volume nucleation with one-dimensional growth) is responsible for the crystallization process for heating rates 5-50 K/min for Se glass and two mechanisms (volume nucleation with two- and one-dimensional growth) are working simultaneously during the amorphous-crystalline transformation of the Ga_2.5Se_97.5 and Ga₅Se₉₅ glasses (5-50 K/min). The reaction model that may describe crystallization process of all the compositions of Ga_xSe_100-x glass system is Avrami-Erofeev model (g(α)=[-ln(1-α)]^1/n) with n=2 for Se glass. While for Ga_2.5Se_97.5 and Ga₅Se₉₅ glasses, the values of n are equal to 3 and 2 for the heating rates 5-20 and 35-50 K/min, respectively. A good agreement between the experimental and the reconstructed (α-T) curves has been achieved. The transformation from amorphous to crystalline phase in Ga_xSe_100-x glass system demonstrates complex multi-step involving several processes.

[en] The results have been presented of investigation into the kinetics and mechanism of crystal growing of pure gallium (99.9999%) and its alloys with 0.01 and 0.1 wt.% indium. The dependences are obtained of the growing rate of faces (001) and (111) on the supercooling for both deformed and nondeformed crystals. In conformity with the previously published studies it has been shown that nondeformed crystals of gallium grow from melt by means of two-dimensional nucleation mechanism. Indium additions decrease the growth rate without changing the crystallization mechanism. At higher growth rates the capture of indium-rich melt by the crystal is observed. The capture layers are parallel to the growing face. The alternation of the layers and their thickness vary with the increase in the growth rate

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[en] Band structure calculations of FeGa_1-xAl_x have been performed, to further investigate the stability of ferromagnetism in FeAl. The Stoner parameter increases by about 20% at the FeGa end. This is also confirmed by our spin-polarized calculations. We conclude that Ga substitution for Al is likely to stabilize the elusive (or illusive) ferromagnetic state in FeAl. [copyright] 2001 American Institute of Physics

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